It seemed almost magical that virtualization technology appeared right on schedule to offer a solution to severe data center problems. For most organizations the nightmare wasn’t that their raw data center costs were escalating, awkward though that was. It was that they might be forced to build a whole new data center long before they had expected to.

Data center space is the most expensive “office space” there is. The actual cost varies according to many factors, particularly size and capacity, but also proximity to power sources, power distribution and disaster recovery, labor costs, local taxes and so on. And the costs are always substantial; measured in mil...